With advancement of the society and development of science and technology, people's life standards are becoming higher and higher. At present, smart homes, ultra-thin televisions, portable speakers and the like electronic products are popular, which all impose a requirement on the thickness of the product. In the aspect of the product structure of the speakers, high-performance thin full-frequency speakers are also desired.
Moving coil speakers are speakers most extensively applied worldwide. A moving coil speaker is formed of a magnetic system and a vibration system. The magnetic system comprises an upper magnetic conduction plate, a magnet and a lower magnetic conduction plate. The vibration system comprises a tampered (or spherical) vibration film and a voice coil. In a traditional voice coil, a conductive coil surrounds a cylindrical frame. Therefore, the thickness of the moving coil speaker includes the heights of the magnetic system and the tampered (or spherical) vibration film, and also includes a portion of the voice coil height. If the moving coil speaker needs to be made thinner, the product performance would be sacrificed, for example, a lower sensitivity, a lower power handling, an increased resonant frequency and the like. As such, the requirements imposed by the currently popular ultra-thin electrode devices on high voice quality and high performance may not be accommodated.
In a traditional planar magnetic film speaker, the magnetic system comprises only a magnet and a lower magnetic conduction plate, and the integral thickness can be made thinner. Since the vibration film and the voice coil are plane-shaped and the thickness is initially small, the total thickness of the product is small. However, since the vibration amplitude of the vibration film in the traditional planar magnetic film speaker is small, which is generally 0.5 mm only, The compliance of the vibration film may only be provided by a pre-tension force of the vibration film and an elastic deformation of the vibration film when the vibration film is adhered to the frame. Therefore, the compliance of the vibration film is small, and the resonant frequency is high. In this way, although the traditional planar magnetic film speaker is thin, the planar magnetic film speaker may be used as a high-frequency speaker only.
Therefore, based on the above factors, how to design a compact and thin full-frequency speaker is a technical problem to be urgently solved for a person skilled in the art.